PEF2V02
2017-11-20
7
3. OPERATING PRINCIPLE
The flow measuring principle is based on ultrasonic measurement method. The ultrasonic signal along the
measuring section moves many times upstream and downstream between the ultrasonic sensors, who alternately
performs transmitter and receiver functions. From the resulting time difference the flow rate is calculated. Measured
flow rate is converted into the pulses quantity that is transferred in output pulse terminal.
4. MARKING AND SEALING
4.1. Marking:
Marking of electronic unit
There are following information on the front panel of electronic unit -
manufacturer’s trade mark, type of
sensor, serial number, year of manufacture, EC-type examination certificate number, accuracy class,
environmental class by LST EN1434-1, electromagnetic and mechanical environmental class, enclosure protection
class, the limiting values of the flow rate (qi,qp,qs), output pulse value, maximum temperature range for flow
sensor, the maximum admissible working pressure.
Numbers of terminal pins are marked close to the terminal
Marking of flow sensor
There are following information on the flow sensor:
-nominal diameter,
- arrow for indication of a flow direction
4.2.
Security seals
:
The following sealing of electronic unit is provided
Manufacturer‘s adhesive seal-sticker on the access to the adjustment activation jumper (see Annex C,
fig.C1, pos.1) and on the fixer on the cover protecting electronic wiring plate (see Annex C, fig.C1, pos.2)
The following measuring section sealing is provided
Manufacturer‘s adhesive seal-sticker on the screws of protective cover of flow sensor (see Annex C,
fig.C2a; b; c; d; e).
Manufacturer‘s hanged seals on ultrasonic transducers for flow sensors with steel body (see Annex C,
fig.C2 f).
Mounting seal
After installation the case and cover of the electronic unit (see Annex C, fig.C1, pos.3) are sealed with two
hanged seals of heat supplier.
5. SAFETY REQUIREMENTS
Before beginning installation works you must to read this document and follow its instructions.
•
Risk factors during the flowmeter installation and service is a heat conveying fluid flowing within flow sensor
with inner pressure up to 1,6 (2,5) MPa and temperature up to 130
0
C.
•
To eliminate this risk the service and installation works must be performed by qualified technical personnel.
Personnel must be familiar with appropriate technical documentation and general safety instructions.
•
It is necessary to follow general safety requirements during installation and maintenance process.
•
Protective grounding is not required, because housing is made from plastics, and conductive parts are not
exposed to the surface.
•
Safety guarantees at installation and service of meter is:
- Reliable insulation of electrical circuits,
- Hermetic fitting of primary flow sensor into the pipeline,
- Reliable fastening of sub-assemblies of heat meter at installation.
Warning! Mounting of the flowmeter is permissible only after ensuring of absence of heat
conveying fluid in the pipeline.
By connecting the flow sensor to the external pulse registration device which is powered via AC
230V check the proper grounding of external device.
